Spring Bean的生命周期管理
一、Spring Bean的生命周期
通过以下方式来指定Bean的初始化和销毁方法, 当Bean为单例时,Bean归Spring容器管理,Spring容器关闭,就会调用Bean的销毁方法 当Bean为多例时,Bean不归Spring容器管理,Spring容器关闭,不会调用Bean的销毁方法
二、通过@Bean的参数(initMethod ,destroyMethod)指定Bean的初始化和销毁方法
1、项目结构
2、Person
public class Person { public Person(){ System.out.println("Person 创建了..."); } public void init(){ System.out.println("Person 初始化了..."); } public void destroy(){ System.out.println("Person 被销毁了..."); } }
3、Bean注册配置类(单实例)
import com.dashu.bean.Person; import org.springframework.context.annotation.*; @Configuration public class BeanConfig { @Bean(initMethod = "init",destroyMethod = "destroy") public Person person(){ return new Person(); } }
4、测试类
import com.dashu.bean.Person; import com.dashu.config.BeanConfig; import org.springframework.context.annotation.AnnotationConfigApplicationContext; public class Main { public static void main(String[] args) { //加载配置类获取容器 AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext(BeanConfig.class); //获取Bean Person bean = annotationConfigApplicationContext.getBean(Person.class); //关闭容器 annotationConfigApplicationContext.close(); } }
5、测试结果
6、Bean注册配置类(多实例)
import com.dashu.bean.Person; import org.springframework.context.annotation.*; @Configuration public class BeanConfig { @Scope("prototype") @Bean(initMethod = "init",destroyMethod = "destroy") public Person person(){ return new Person(); } }
7、测试结果
三、Bean实现接口InitializingBean, DisposableBean
1、Person
import org.springframework.beans.factory.DisposableBean; import org.springframework.beans.factory.InitializingBean; public class Person implements InitializingBean, DisposableBean { public Person(){ System.out.println("Person 创建了..."); } @Override public void afterPropertiesSet() throws Exception { System.out.println("Person 初始化了..."); } @Override public void destroy() throws Exception { System.out.println("Person 被销毁了..."); } }
2、Bean注册配置类
import com.dashu.bean.Person; import org.springframework.context.annotation.*; @Configuration public class BeanConfig { @Bean public Person person(){ return new Person(); } }
3、测试结果
四、通过注解@PostConstruct和@PreDestroy
@PostConstruct:标注在Bean的初始化方法上 @PreDestroy:标注在Bean的销毁方法上
1、Person
import javax.annotation.PostConstruct; import javax.annotation.PreDestroy; public class Person { public Person(){ System.out.println("Person 创建了..."); } @PostConstruct public void init(){ System.out.println("Person 初始化了..."); } @PreDestroy public void destroy(){ System.out.println("Person 被销毁了..."); } }
2、测试结果
五、使用接口BeanPostProcessor实现类(后置处理器)
1、项目结构
2、Person
import org.springframework.stereotype.Component; import javax.annotation.PostConstruct; import javax.annotation.PreDestroy; @Component public class Person { public Person(){ System.out.println("Person 创建了..."); } @PostConstruct public void init(){ System.out.println("Person 初始化了..."); } @PreDestroy public void destroy(){ System.out.println("Person 被销毁了..."); } }
3、Bean注册配置类
import org.springframework.context.annotation.*; @Configuration @ComponentScan({"com.dashu"}) public class BeanConfig { }
4、BeanPostProcessor实现类(后置处理器)
import org.springframework.beans.BeansException; import org.springframework.beans.factory.config.BeanPostProcessor; import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessor; import org.springframework.lang.Nullable; import org.springframework.stereotype.Component; /** * 后置处理器:初始化前后进行处理工作 */ @Component public class MyBeanPostProcessor implements BeanPostProcessor { /** * 初始化之前工作 * @param bean * @param beanName * @return * @throws BeansException */ @Override public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { System.out.println("初始化之前..."+beanName+"=["+bean+"]"); return bean; } /** * 初始化之后工作 * @param bean * @param beanName * @return * @throws BeansException */ @Override public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { System.out.println("初始化之后..."+beanName+"=["+bean+"]"); return bean; } }
5、测试结果
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